When carrying out electrophoretic dip coating it should be possible to bring the objects which are to be coated to different potentials during the passage through the dip tank. This is on the one hand connected with the fact that during the actual immersion operation different regions of the object which is to be coated come into contact with the coating fluid for periods of different length and regions with different coating thicknesses would therefore result in the absence of appropriate countermeasures. On the other hand the fact that the deposited layer thickness and the electrical contact resistance increase and therefore the deposition speed decreases as the objects pass through the dip tank is taken into account by the different voltage which is applied to the objects. The bus bar arrangement of known electrophoretic dip coating plant is therefore generally divided into different regions which can be brought to different potentials. In this respect steps should be appropriately taken to ensure that at the moment at which the objects which are to be coated pass over from one region of the bus bar arrangement to the adjacent one both regions lie at the same potential; otherwise dangerous sparks could occur.
In the case of known electrophoretic dip coating plant of the type initially mentioned which are currently on the market each region of the bus bar arrangement is fed by a particular rectifier with which a particular electronic voltage regulating unit is associated. This is relatively expensive at the current strengths which are required for electrophoretic dip coating.
The present invention is directed to solving these and other matters.